"We discovered an advanced attack on our own internal networks. It was complex, stealthy, it exploded several zero-day vulnerabilities, and we're quite confident that there's a nation state behind it,"Kaspersky Lab CEO and founder Eugene Kaspersky wrote in a blog post.

The Moscow-based anti-virus software provider termed this attack as Duqu 2.0. Duqu is named after a specific series of malware which was considered to be related to the Stuxnet attack that targeted states like Iran, India, France, and Ukraine in 2011.

The blog post says that the attackers had tried to infiltrate Kaspersky's networks to learn more about its services and new technologies. Although the firm said that it would continue to sweep and probe its networks, Kaspersky, in the blog post, wrote that data it had seen was "in no way critical to the operation" of the company's products.

In a separate release, the company confirmed that it is confident that its clients and partners are safe and that there is no impact on the company's products, technologies and services.